Featured Research

from universities, journals, and other organizations

Sandia Scientist, Colleague, Suggest Meteor Plumes Causing Transient Dark Spots In Upper Atmosphere

Date:
February 11, 1998
Source:
Sandia National Laboratories
Summary:
A Sandia National Laboratories physicist and his Texas-based research colleague have done some calculations that may offer additional insight into a decade-old astronomical controversy about whether up to 30,000 house-sized snowballs, or icy comets, are striking Earth each day.

ALBUQUERQUE, N.M. -- A Sandia National Laboratories physicist and his Texas-based research colleague have done some calculations that may offer additional insight into a decade-old astronomical controversy about whether up to 30,000 house-sized snowballs, or icy comets, are striking Earth each day.

That theory has been proffered by two space scientists, Louis Frank and John Sigwarth of the University of Iowa, based on observations by the Dynamics Explorer-1 satellite of transient dark spots, or holes, in the upper atmosphere's far-ultraviolet dayglow emission.

Such a tremendous influx of small comets has never been observed. These water-bearing objects would add phenomenal quantities of water to Earth. If this could indeed be shown to be happening, much of what is known about comet creation and the origins of the oceans, terrestrial life, and perhaps even of the solar system might need revision.

The interpretations have been met with much scientific skepticism, but Frank and Sigwarth weighed in last May with more evidence - observations by the NASA satellite Polar that they said provide new support for the existence of the dark holes. A number of former critics became converts.

Now, however, Sandia physicist Mark Boslough and Randy Gladstone of the Southwest Research Institute in San Antonio, Tex., have published a study that provides a less provocative - but still scientifically interesting - explanation for the so-called atmospheric holes.

They may be plumes, not holes, and meteoroids may be the source.

Their computational simulations, which make use of Sandia's shock physics code CTH and Boslough's earlier work with Sandia colleague Dave Crawford in successfully predicting the visible plumes from Comet Shoemaker-Levy 9's impact into Jupiter in 1994, suggest that the entry of ordinary meteoroids can form dark spots very similar to those reportedly observed by the satellite instruments.

Their study is published in the Dec. 15 Geophysical Research Letters, along with four other studies by other scientists that together the journal say provide "five independent tracks of evidence that are entirely inconsistent with a huge bombardment by small comets." The journal says the five studies together "refute this [the small comets] hypothesis."

Boslough and Gladstone reject the assumption, central to the small comets hypothesis, that the observed darkening is caused by absorption of water vapor above the atmosphere. Instead, they believe that atomic oxygen, which is the source of the dayglow, is momentarily displaced by the passage of meteoroids. Normal air from lower altitudes contains oxygen in its molecular form and is black in the wavelength that the satellite sees.

They propose that when a stony object as small as 50 centimeters across collides with the atmosphere and plunges into the lower layers, it ejects a very thin plume of this "black" air to as high as 1,000 kilometers. It is these dark plumes, they suggest, that are being detected by the satellites.

Their work is preliminary and they acknowledge that the hypothesis doesn't account for the observed high rate of dark hole formation. But they say if they can show their idea is correct for large meteoroids, they will look into the possibility that small ones have a similar effect.

The two scientists also propose a test of their hypothesis. They say if they are right, it is just a matter of time before Department of Defense satellites detect an infrared flash from a large meteor that corresponds exactly to the time and location of one of the holes.

"We expect that satellite data on atmospheric holes in the FUV [far ultraviolet] will confirm the existence of [high-altitude] plumes that are continuously being generated by meteors."

The four other new papers that also undermine the small comets hypothesis are based on lack of any evidence for frequent comet bombardment on the moon, no sign of the high abundance of noble gases in the upper atmosphere that would be expected from a high rate of comet bombardment, absence of visible light observations, and evidence that the source of dark pixels in the Polar spacecraft's ultraviolet camera is internal to the camera system.

Three of these papers are by scientists at the Lunar and Planetary Laboratory at the University of Arizona, and one is by scientists at the Universities of Alabama and Washington and NASA Marshall Space Flight Center.

Frank and Sigwarth, however, still strongly stick to their small comets hypothesis - they particularly dispute that the dark spots are instrumental artifacts - and the controversy is likely to continue for some time.

Sandia is a multiprogram DOE laboratory, operated by a subsidiary of Lockheed Martin Corp. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major research and development responsibilities in national defense, energy, environmental technologies and economic competitiveness.


Story Source:

The above story is based on materials provided by Sandia National Laboratories. Note: Materials may be edited for content and length.


Cite This Page:

Sandia National Laboratories. "Sandia Scientist, Colleague, Suggest Meteor Plumes Causing Transient Dark Spots In Upper Atmosphere." ScienceDaily. ScienceDaily, 11 February 1998. <www.sciencedaily.com/releases/1998/02/980211072845.htm>.
Sandia National Laboratories. (1998, February 11). Sandia Scientist, Colleague, Suggest Meteor Plumes Causing Transient Dark Spots In Upper Atmosphere. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/1998/02/980211072845.htm
Sandia National Laboratories. "Sandia Scientist, Colleague, Suggest Meteor Plumes Causing Transient Dark Spots In Upper Atmosphere." ScienceDaily. www.sciencedaily.com/releases/1998/02/980211072845.htm (accessed July 31, 2014).

Share This




More Space & Time News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Supply Ship Takes Off for International Space Station

Supply Ship Takes Off for International Space Station

AFP (July 30, 2014) The European Space Agency's fifth Automated Transfer Vehicle (ATV-5) is takes off to the International Space Station on an Ariane 5 rocket from French Guiana. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Raw: Rocket Launches Into Space With Cargo Ship

Raw: Rocket Launches Into Space With Cargo Ship

AP (July 30, 2014) Arianespace launched a rocket Tuesday from French Guiana carrying a robotic cargo ship to deliver provisions to the International Space Station. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins